Consolidated Condensed Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Receivables, allowance for uncollectables	$ 2.6	$ 2.6
Common equity, par value	$ 1	$ 1
Common equity, shares authorized	400.0	400.0
Common equity, shares outstanding	216.6	215.8
Tampa Electric Co [Member]
Receivables, allowance for uncollectables	$ 1.2	$ 1.3